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APIs · head to head

Asyncapi vs OWASP ZAP

Asyncapi logo

Asyncapi

APIs

Specification and tools for defining asynchronous APIs

From
Free
Rated
-
Full reviewWebsite
OWASP ZAP logo

OWASP ZAP

Cybersecurity

Free, open-source web application scanner and intercepting proxy, now governed by the Software Security Project.

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Asyncapi complex to implement and debug asynchronous operations due to their non-linear and concurrent nature; OWASP ZAP authenticated scanning of modern single-page applications is the hard part and ZAP makes you build it by hand: session handling, token refresh and login scripts are configured per application, and a misconfigured session means the scanner logs itself out and reports a clean result for pages it never reached.
  • They diverge on capability: Asyncapi covers API Specification, OWASP ZAP covers Intercepting proxy.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Asyncapi and OWASP ZAP actually diverge.

Attributes where Asyncapi and OWASP ZAP differ
AttributeAsyncapiOWASP ZAP
Pricing modelopen-sourcefree
PlatformsWeb, CLI, IDE ExtensionsDesktop, Cli, Api
CategoryAPIsCybersecurity
Founded20192001

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Asyncapi

  • API Specification
  • Code generation
  • Documentation
  • Multiple messaging protocols
  • Code generators
  • Specification support
  • Tools support
  • CLI support

Only in OWASP ZAP

  • Intercepting proxy
  • Passive scanner
  • Active scanner
  • AJAX spider
  • Automation Framework
  • Headless daemon and REST API
  • Docker images
  • Add-on marketplace

What people use each for

The jobs each tool is most often brought in to do.

Asyncapi

  • API Developmentnot OWASP ZAP
  • API Gatewaynot OWASP ZAP
  • API Testingnot OWASP ZAP
  • API Documentationnot OWASP ZAP
  • Microservicesnot OWASP ZAP

OWASP ZAP

  • Adding a baseline security scan to every application's pipeline where per-target commercial licensing would limit coverage to a handfulnot Asyncapi
  • Manual penetration testing that needs an intercepting proxy, request replay and fuzzing without a paid licence per testernot Asyncapi
  • Teaching developers what an attack against their own endpoint looks like, using a tool they can install themselvesnot Asyncapi
  • Pre-release regression scanning of an internal application that would never justify a commercial DAST subscriptionnot Asyncapi

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Asyncapi

  • Complex to implement and debug asynchronous operations due to their non-linear and concurrent nature
  • Keeping AsyncAPI documents up to date is challenging as systems evolve
  • Tracing and debugging asynchronous operations is more difficult than synchronous request-response patterns

OWASP ZAP

  • Authenticated scanning of modern single-page applications is the hard part and ZAP makes you build it by hand: session handling, token refresh and login scripts are configured per application, and a misconfigured session means the scanner logs itself out and reports a clean result for pages it never reached.
  • There is no support contract in the product, so when a scan breaks the day before a release the escalation path is a GitHub issue and a community chat, which is not an answer that satisfies a delivery manager or an auditor who wants a named responsible party.
  • Active scanning sends genuine attack traffic, so it can create records, trigger emails, exhaust rate limits or destabilise a fragile environment, and pointing it at production without prior agreement produces an incident rather than a test result.
  • Output needs triage: passive rules generate large volumes of low-severity informational findings about headers and cookie flags that bury the few results that matter, and a team without someone tuning the rule set stops reading the report within a few sprints.
  • As a dynamic scanner it can only test what it can reach, so authorisation flaws between accounts, business logic abuse and anything behind an undiscovered endpoint go unreported, and a passing ZAP scan is evidence of nothing more than the absence of the classes of bug it looks for.

Pricing, plan by plan

Asyncapi

Free
  • Open SourceFree
    • AsyncAPI specification
    • Tools
    • Community support

OWASP ZAP

Free
  • Free & Open SourceFree
    • Full functionality
    • Active & passive scanning
    • Spider

Which should you pick?

Choose Asyncapi if

  • You need api specification.
  • You want to start without paying.
  • You work on Web, CLI, IDE Extensions.
  • You also want code generation.
Asyncapi review

Choose OWASP ZAP if

  • You need intercepting proxy.
  • You want to start without paying.
  • You work on Desktop, Cli, Api.
  • You also want passive scanner.
OWASP ZAP review

Questions people ask

Is Asyncapi or OWASP ZAP better?
Neither clearly leads. Asyncapi starts at Free and OWASP ZAP at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Asyncapi or OWASP ZAP?
Asyncapi starts at Free and OWASP ZAP at Free.
Does Asyncapi or OWASP ZAP run on more platforms?
Asyncapi runs on Web, CLI, IDE Extensions. OWASP ZAP runs on Desktop, Cli, Api.
Can I use Asyncapi for free?
Both have a free tier, so you can try either at no cost before committing.
What is Asyncapi best used for?
Asyncapi is most often used for api development, api gateway, api testing, api documentation. Of those, api development and api gateway are not what OWASP ZAP is typically brought in for.
What can Asyncapi do that OWASP ZAP cannot?
Asyncapi covers API Specification, Code generation, Documentation, Multiple messaging protocols. OWASP ZAP covers Intercepting proxy, Passive scanner, Active scanner, AJAX spider.

Answered from the vendors’ own pages

Asyncapi: What is AsyncAPI used for?

AsyncAPI is an open-source specification for defining and documenting asynchronous APIs, message-driven systems, and event-driven architectures. It serves the same purpose for async APIs as OpenAPI does for REST APIs, providing standardized documentation, code generation, and tooling.

Source
OWASP ZAP: Is it still called OWASP ZAP?

The project left OWASP in August 2024 and is now governed by the Software Security Project, with core development sponsored by Checkmarx. The tool is now just ZAP, though most existing documentation, courses and search results still use the OWASP name.

Asyncapi: Is AsyncAPI free to use?

Yes, AsyncAPI is completely free and open-source. It is hosted by the Linux Foundation and supported by community contributions and sponsorships from companies like Postman, IBM, IQVIA Technology, and Solace.

Source
OWASP ZAP: Is it free for commercial use?

Yes. It is Apache 2.0 licensed, with no per-application, per-scan or per-user cost, and it can be used and modified commercially without a licence agreement.

Asyncapi: What protocols and technologies does AsyncAPI support?

AsyncAPI supports multiple protocols and technologies including Kafka, RabbitMQ, MQTT, Socket.IO, AWS EventBridge, and others. It provides language support for JavaScript/TypeScript, Python, Java, Go, C#/.NET, Kotlin, and PHP.

Source
OWASP ZAP: Can it replace a penetration test?

No. It automates checks for known vulnerability classes against endpoints it can reach. It does not reason about business logic, chain findings into an attack, or test authorisation between accounts, which is most of what a tester actually does.

Asyncapi: Does AsyncAPI have IDE support?

Yes, AsyncAPI has IDE extensions available for VSCode and IntelliJ, along with CLI utilities and GitHub Actions integration for developers.

Source
OWASP ZAP: Does it run in CI?

Yes, through the official Docker images and the Automation Framework, which defines scan jobs in YAML so configuration lives in the repository. A baseline passive scan is the usual starting point because it is fast and non-intrusive.

OWASP ZAP: How does it compare to Burp Suite?

Burp Suite Professional is the more polished manual testing tool and has a stronger scanner and extension ecosystem, but it is licensed per tester and Burp Suite Enterprise per target. ZAP is the better fit where cost per target is the binding constraint; many teams use both.

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